Anti-capitalist demonstrators have started fires and smashed windows in the City of London.

Police said at least 32 people who gathered in London's financial district for a protest on the eve of the G20 summit were arrested after violent clashes.

Fires broke out on the streets and an effigy of a City banker was set ablaze after riot police hemmed in a group of demonstrators near the Bank of England.

Senior officers have vowed to prosecute a small group of protesters, some wearing bandanas and hoodies, who smashed windows at a Royal Bank of Scotland office.

Smoke bombs were hurled into the building and some protesters entered, with Scotland Yard officers following around 15 minutes later 'in support of building security'.

Two people were held for aggravated burglary over the raid on the RBS building in Threadneedle Street and two for public order offences.

Others were held for threatening behaviour, possession of drugs, violent disorder and blocking a road. Eleven people were arrested on Wednesday morning after police uniforms were found in the back of an armoured vehicle.

Around 4,000 people demonstrated in the streets around the Bank of England and many were penned in as riot vans blocked off roads.

At least one officer was seen with blood spurting from a cut on his forehead after crowds pelted police with empty beer cans.

Met Police Commander Simon O'Brien said the ringleaders were followed by helicopter as they left flashpoints and they could expect 'a knock on the door'.

He said: 'As we went on it was clear there were people within the group that were first of all involved in juvenile and puerile behaviour.

'That started to escalate into quite provocative behaviour towards police lines. There were small groups charging forwards and backwards into police lines.'

'It did seem to us from CCTV and police on the scene that they tried to find a way to ramp up the protest and hijack it into violence. We believe these were the sort of people we have been monitoring on the internet and on-line prior to today.'

The Following Nations are Represented in London for the Conference in the docklands tommorow

Mr Mirek Topolanek, Prime Minister of The Czeck Republic is representing the European Union

I've heard about this and it's just "professional protesters" going nuts in order to give the impression that they represent the "will of the people." Hopefully, nobody falls for it, but you know they will.

Also, when viewing the news footage, if you see protesters with bloody faces, then be aware that some of them actually pour theatrical blood on themselves to give the impression that they are being brutalized by police.

I've heard about this and it's just "professional protesters" going nuts in order to give the impression that they represent the "will of the people." Hopefully, nobody falls for it, but you know they will.

Also, when viewing the news footage, if you see protesters with bloody faces, then be aware that some of them actually pour theatrical blood on themselves to give the impression that they are being brutalized by police.

No, the violent ones are just using the Demonstration as a cover to vandalize and steal. Sounds like a few juviniles thought it would be funny to smash up afew bank offices.

They wont be the anarchists or the real demonstrators...they will be the ones who just want to riot...if they get smacked in the face by riot police they deserve it.

If it was professional protestors, the police would have cleared the entire City...sound like they arrested a few out of a few thousand. This isnt a riot, just sheer opportunism

btw...interesting that the President of The United Nations isnt invited to the Gathering dont you think